"President Bush moved one step closer to a constitutional showdown with Democrats on Thursday, as the White House asserted executive privilege in refusing to comply with congressional subpoenas for documents related to the dismissal of federal prosecutors," the New York Times is set to report on Friday's front page. Excerpts:

The move prompted Democrats to accuse the White House of stonewalling, and seemed to put the legislative and executive branches on a collision course that could land them in court. It was only the second time in Bush's presidency that he has formally asserted executive privilege, the power first recognized by the Supreme Court in a 1974 Watergate-era case.

On Thursday morning, the White House counsel, Fred F. Fielding, telephoned the Democratic chairmen of the House and Senate Judiciary Committees, which had issued the subpoenas, to inform them of Bush's decision. The president also intends to invoke executive privilege to prevent two of his former top aides, Harriet E. Miers, the former White House counsel, and Sara Taylor, the former political director, from testifying, officials said.

"With respect, it is with much regret that we are forced down this unfortunate path," Fielding wrote in a letter to the respective committee chairmen, Sen. Patrick J. Leahy of Vermont and Rep. John Conyers Jr. of Michigan. He complained the committees had issued "unfettered requests."

Conyers, in a telephone interview, called the Fielding letter "an appalling response to a reasonable question," adding, "This is reckless, it's a form of governmental lawlessness that is really astounding."